The invention relates to power distribution networks.
Reclosers are used in an electrical power distribution network to detect faults in the network and isolate a device or load from the distribution network upon detection of the fault.
The invention provides a control system for an intelligent power distribution network. The distribution network includes multiple branches, each of which is connected to a power source, electrical devices connected to the branches, and a normally-open device connected between two or more branches. The control system includes control elements, each control element being associated with an electrical device connected to a branch of the distribution network. The control system also includes a master control element associated with the normally-open device, the master control element communicating with the control elements. When a fault occurs on the distribution network, the master control element prevents the normally-open device from closing when information from the control elements indicate that conditions potentially disruptive to the distribution network would occur if the normally-open device closed. Moreover, the master control element permits the normally-open device to close when information from the control elements indicate that conditions potentially disruptive to the distribution network would be avoided if the normally-open device were closed.
Embodiments may include one or more of the following features. For example, a branch may include a corresponding load. The power source connected to a branch may provide a primary source of power to the corresponding load of the branch under predetermined operating conditions of the network. Alternatively, the power source connected to a branch may provide an auxiliary source of power to the corresponding load of the branch under predetermined operating conditions of the network. A control element may include a sensor that detects whether a fault occurs at the associated electrical device.
The electrical device may include a switching system that is controllably switched between a normal operating position and a fault operating position. When the electrical device is in the normal operating position, a load associated with the electrical device may be supplied power from the power source coupled to the electrical device. The control element may switch the electrical device to the fault operating position when the control element detects that a fault occurs at location that would disrupt power supplied to the associated load. Otherwise, the control element may switch the electrical device to the fault operating position in response to data from the master control element.
The master control element may communicate with a control element through a radio link. Likewise, the master control element may communicate with a control element through a fiber optic link. Or, the master control element may communicate with a control element through an electrical wire.
The master control element may reconfigure the power distribution network based on information from the control elements. Reconfiguration may include determining a direction of current flow through the electrical device. Reconfiguration may include accounting for changes in the direction of current flow through the electrical device.
Reconfiguration may include a primary reconfiguration that reconfigures an electrical device on the power distribution network independently of the configuration of other electrical devices and the normally-open device. Primary reconfiguration of the electrical device may be based on a voltage and a current measurement at the electrical device. Reconfiguration may include a secondary reconfiguration that reconfigures an electrical device on the power distribution network based on input from the master control element. The master control element may determine whether to reconfigure the network using the primary or secondary reconfiguration based on whether communication between any of the electrical devices or the normally-open device is active.
The master control element may monitor parameters in the power distribution network local to the normally-open device. The master control element may update a configuration of the power distribution network. The master control element may include a general purpose computer.
Conditions potentially disruptive to the power distribution network may include load conditions that exceed the capacity of the power distribution network. The normally-open device may include a tie recloser.